The invention concerns an apparatus for the production of granulates from a flowable, viscous mass which is brought into drop form and caused to solidify. The apparatus includes a vessel having a plurality of outlet orifices, which are intermittently opened or closed by covering surfaces moved periodically in front of them to periodically permit the discharge of drops of mass which is under pressure.
Apparatuses of this type are known from U.S. Pat. No. 2,979,764, for example. In the known configuration a disk is equipped with three blades, each covering a sector of 60.degree.. The disk rotates at the bottom of a pressure vessel having a perforated bottom. By means of the rotating motion of the bladed disk, the material which initially flows from the vessel through the perforations in the form of strips, is cut into individual pieces, which then form the drops. A disadvantage is that such installations cannot be used in combination with conveyor belts passing under the masses dripping out, because non-uniform amounts of drops are formed as viewed over the cross-section of the belt, which would lead to the agglomeration of several drops.
Granulating devices equipped with rolls (e.g., see U.S. Pat. Nos. 1,848,332 and 4,279,579) have therefore been proposed, wherein drops exiting from several holes may be placed uniformly onto a support surface. In one case, however, (i.e., U.S. Pat. No. 1,848,332), the process is restricted to relatively viscous masses, while less viscous masses would run from the orifices out of control. In the other case (i.e., U.S. Pat. No. 4,279,579) this disadvantage is not encountered, but it is found that at high production velocities and relatively viscous masses, the outer rotating and perforated cylindrical body entrains part of the mass, which then drops onto the cooling conveyor or the like in the form of fine droplets, potentially leading to undesirable bonding or affecting the shape of the drops and/or their removal from the conveyor.
It is, therefore, an object of the invention to provide an apparatus for the production of granulates of the afore-described type such that even in the case of very high production rates and drop velocities, the spattering of residual droplets is avoided.